Building waves (incomeb, 2014–2020) ...
  2014: n=  8427, internet rate= 49.8%
  2016: n=  4123, internet rate= 77.4%
  2018: n=  8747, internet rate= 78.8%
  2020: n=  7484, internet rate= 86.3%

Individuals observed in ≥2 waves: 8088
  Ever-switchers (change online status across waves): 2168 (26.8%)
  Person-wave observations: 28781
  -> FE identified off 2168 switchers (vs 655 in the 2-wave panel).

(1) Pooled OLS (all 4 waves, year dummies, entity-clustered):
    internet b=+0.1252*** (SE=0.0149, p=0.000)  ~+13.3%

(2) Individual FE + year FE (within estimator, entity-clustered):
    internet b=-0.0754** (SE=0.0353, p=0.033)  ~-7.3%
    N obs=28781, entities=17232.0, within R²=0.0051

(3) Individual FE on switcher subsample only:
    internet b=-0.0104 (SE=0.0327, p=0.750)  ~-1.0%   (N=5530, entities=2168.0)

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Compare: 2-wave FE was −0.002 (p=0.97) off 655 switchers.
This 4-wave panel multiplies switchers and sharpens the within estimate.
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